## Initial concentrations are the same at equilibrium?

Tai Metzger 3K
Posts: 103
Joined: Sat Aug 24, 2019 12:17 am

### Initial concentrations are the same at equilibrium?

I was doing some practice problems and for a couple I found that x was found to be so small that the concentrations for the reactants were the same at equilibrium as they were initially. Is this possible and/or common? Thanks!

KeyaV1C
Posts: 103
Joined: Sat Aug 17, 2019 12:17 am
Been upvoted: 1 time

### Re: Initial concentrations are the same at equilibrium?

When K is really small, the value of x tends to be really small as well, barely changing the concentration of the reactants.

Marni Kahn 1A
Posts: 107
Joined: Thu Jul 25, 2019 12:17 am
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### Re: Initial concentrations are the same at equilibrium?

This is seen quite often because we do a lot of examples with an infinitesimally small value of Ka

Morgan Carrington 2H
Posts: 54
Joined: Wed Nov 14, 2018 12:22 am

### Re: Initial concentrations are the same at equilibrium?

It is possible and commonly seen when doing acid and/or base equilibrium, but I would warn to be careful getting comfortable doing it because there are times when you can't use that rule.